R/FTUna.R

In ftaproxim: Fault Tree Analysis Based on Proxel Simulation

#' Fault Tree Unavailability
#'
#' This function returns a list where the first element is a data frame of unavailabilities
#' and the second element is the plot of the unavailabilities
#'
#' @param belist a list containing all the basic components of a fault tree
#' @param mcs a list of minimal cuts sets
#' @param totaltime an integer value for the total time
#' @param delta a numeric value as time step
#' @param tol a numeric value for the tolerance level
#'
#' @return  A list of unavailabilities for the basic events as well as the system,
#'          and their plots againts time steps
#'
#'
#' @examples
#' A<-list(
#'  states=c("OK","F"),
#'  G=rbind(c(NA,1),
#'          c(1,NA)),
#' dist=c("exp", "exp"),
#'  param=list(c(0.1), c(1))
#' )
#'
#' B<-list(
#'  states=c("OK","F"),
#'  G=rbind(c(NA,1),
#'          c(1,NA)),
#'  dist=c("exp", "exp"),
#'  param=list(c(0.01), c(2))
#' )
#'
#'
#' C<-list(
#'  states=c("OK","F"),
#'  G=rbind(c(NA,1),
#'          c(1,NA)),
#'  dist=c("exp", "weibull"),
#' param=list(c(0.1), c(5,2))
#' )
#'
#' D<-list(
#'  states=c("OK", "F"),
#'  G=rbind(c(NA, 1),
#'          c(1,NA)),
#'  dist=c("lnorm", "exp"),
#'  param=list(c(2, 0.1), 2)
#' )
#'
#' BElist<-list(A,B,C,D)
#' names(BElist)<-c("A","B","C","D")
#' MCS<-list(c("A", "C", "D"), c("B", "C", "D"))
#'
#' x<-FTUna(BElist, MCS, 5, 0.2, 1e-07)
#'
#' # Unavailabilities
#' x$Unavailability
#'
#' #Plots
#' x$Plot
#'
#' @importFrom ggplot2 ggplot aes theme geom_line xlab
#' @export
FTUna <- function(belist, mcs, totaltime, delta, tol) {
  una <- NULL
  for (i in names(belist)) {
    BE <- belist[[i]]
    out <- ProxelBE(BE, "F", totaltime, delta, tol)
    una <- cbind(una, out)
  }
  colnames(una) <- names(belist)
  te <- 0
  for (i in 1:length(mcs)) {
    if (length(mcs[[i]]) == 1) {
      p <- una[, mcs[[i]]]
    } else {
      p <- apply(una[, mcs[[i]]], 1, prod)
    }
    te <- p + te
  }
  outUna <- as.data.frame(cbind(una, TE = te))
  timeSteps <- totaltime / delta
  df <- NULL
  for (i in 1:ncol(outUna)) {
    dfp <- data.frame(Unavailability = outUna[, i], Time = 1:timeSteps, Event = names(outUna)[i])
    df <- rbind(df, dfp)
  }
  p <- ggplot(df, aes(x = df$Time))
  p <- p + geom_line(aes(y = df$Unavailability, colour = df$Event, linetype = df$Event), size = 0.75)
  p <- p + theme(legend.position = "top") + xlab(label = "Time Steps")

  out <- list(Unavailability = outUna, Plot = p)
  return(out)
}